This research project deals with the regulation of carbohydrate metabolism in the parasitic helminth, Ascaris suum. Glycogen metabolism, glycolytic flux and mitochondrial energy-producing reactions are being studied in an attempt to delineate mechanisms which coordinate their rates of activity. Studies are being carried out on in vitro and in vivo perfusion systems of the muscle of the parasite. Levels of active and inactive glycogen synthase and glycogen phosphorylase are being monitored under various conditions to determine the regulatory signal(s) which initiate(s) glycogen breakdown on synthesis. In addition, the glycolytic enzyme, phosphofructokinase, will be purified from the muscle of Ascaris suum and will be characterized from a kinetic standpoint. The data obtained from this investigation will be correlated with that obtained in the glycogenolysis study on the regulation of phosphorylase b.